Multistage compressor



H. A. FELDBUSH MULTISTAGE COMPRESSOR v Filed June 19, 1954.

June 9, 1936.

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Patented June 9, 1936 UNITED STATES PATENT OFFICE MUL'rIs'rAGECOMPRESSOR Application June 19, 1934, Serial No. 731,240

1 Claim.

This invention relates to air or gas compressors and more particularlyto multi-stage compressors wherein two-stage pistons are connected inline for unitary movement.

An object of the present invention is to provide in a multi-stagecompressor as specified a bleedoff space between the high stage and lowstage cylinders of the compressors, with a suitable tight packingstructure about the high stage piston to prevent leakage from the highstage cylinder into the low stage cylinder.

Another object of the present invention is to provide a novelself-aligning connection between the low stage piston and the high stagepiston for permitting the maintaining of the pistons in alignment or forcompensating for any misalignment between them.

With these and other objects in view as may appear from the accompanyingspeciiication, the invention consists of various features ofconstruction and combination of parts, whichwill be rst described inconnection with the accompanying drawing, showing multi-stagecompressors of the preferred form, and the features forming theinvention will be specifically pointed out in the claim.

In the drawing:

Fig. 1 is a longitudinal section through the cylinder construction of amulti-stage compressor constructed in accordance with the presentinvention.

Fig. 2 is a cross section taken on the line 2--2 of Fig. l.

Fig. 3 is a cross section taken on the line 3--3 of Fig. 1.

Referring more particularly to the drawing, I indicates the low stage orlow pressure cylinder of a multi-stage compressor. 'I'he low pressurepiston 2 reciprocates in the low pressure cylinder I, and it isconnected through the medium of the connecting rod 3 with any suitableoperating mechanism (not shown) The cylinder I is tted with any approvedtype of valves as indicated at 4 and operates, by the reciprocation ofthe piston 2 to compress any suitable air or gas in the first or lowpressure stage of the multi-stage compressor. A high pressure cylinder 5is also provided which is positioned in line with the low pressurecylinder I and is connected thereto through the medium of the connectionextension 6 formed on the high pressure cylinder 5 and the head 1 of thelow pressure cylinder. The head 'I is at the head end of the lowpressure cylinder. A piston or plunger 8 reciprocates in the lowpressure cylinder 5 and it extends through the crank end of the lowpressure cylinder and into the cylinder head 1 when it is in itsretracted position. The piston 8 has an extension or connector 9 thereonwhich is in effect a part of the plunger or piston, being of the samediameter. However, if it is so (Cl. 23o-199) desired, any suitable typeof connector may be employed in lieu of the section of the piston 8 asshown in the drawing. The extension of the piston 8 or connector 9 isconnected by means of an aligning joint IIJ with the low pressure piston2 5 so as to compensate for any slight misalignment between the pistons2 and 8.

The joint I comprises a flanged stem II which extends into the couplingI2 and is held therein against longitudinal movement by the clamping nutI4 which engages against the ilange I5 formed on the inner end of thestem I I. As clearly shown in Figs. 1 and 2 of the drawing, the bore ofthe nut I4 is larger in diameter than the stem Il providing theclearance space I6 and also the bore of the coupling 9 is larger thanthe diameter of the flange I which, together with the clearance I6, willpermit relative lateral movement of the stem II and coupling I2 tocompensate for any slight misalignment of the pistons 2 and 8.

The coupling or connecting extension 6 has a bleed-off space or chamber20 formed therein into which any leakage, past the piston 8 from thehigh pressure cylinder 5, may pass. The bleedoff chamber 2|] may be opento atmosphere through suitable ports as indicated at 2I or these portsmay be closed by suitable caps 22. If it is so desired the bleed-oilchamber 20 may be connected by any suitable means (not shown) to anysuitable place, without departing from the spirit of the invention,since the invention comprises essentially the provision of the space orchamber 20 between the high and low pressure cylinders for receiving theleakage from the high pressure cylinder. As clearly shown in Fig. l ofthe drawing, the piston 8, in its retracted position extends into andthrough the cylinder head l. For the purpose of preventing any leakagefrom the chamber 20 into the low pressurecylinder I, a packing structure23 of any approved type is carried by the cylinder head 1 and surroundsthe piston 8 and its connector or extension 9.

It is to be understood that the high pressure cylinder 5 is providedwith any approved type of intake and discharge valves.

It willI be understood that the invention is not to be limited to thespecific construction or arrangement of parts shown but that they may bewidely modified within the invention defined by the claim.

What is claimed is:

In a multi-stage compressor, in combination, a low pressure cylinder,ahgh pressure cylinder connected in line to said low pressure cylinder,a low pressure piston, a high pressure piston, a 55 bleed-off chamberbetween said cylinders, and open to said high pressure cylinder toreceive any leakage passing said high pressure piston.

HARRY A. FELDBUSH.

